2 * security-core-clr.c: CoreCLR security
5 * Mark Probst <mark.probst@gmail.com>
6 * Sebastien Pouliot <sebastien@ximian.com>
8 * Copyright 2007-2009 Novell, Inc (http://www.novell.com)
11 #include <mono/metadata/class-internals.h>
12 #include <mono/metadata/security-manager.h>
13 #include <mono/metadata/assembly.h>
14 #include <mono/metadata/appdomain.h>
15 #include <mono/metadata/verify-internals.h>
16 #include <mono/metadata/object.h>
17 #include <mono/metadata/exception.h>
19 #include "security-core-clr.h"
21 gboolean mono_security_core_clr_test
= FALSE
;
24 security_critical_attribute (void)
26 static MonoClass
*class = NULL
;
29 class = mono_class_from_name (mono_defaults
.corlib
, "System.Security",
30 "SecurityCriticalAttribute");
37 security_safe_critical_attribute (void)
39 static MonoClass
*class = NULL
;
42 class = mono_class_from_name (mono_defaults
.corlib
, "System.Security",
43 "SecuritySafeCriticalAttribute");
50 * mono_security_core_clr_check_inheritance:
52 * Determine if the specified class can inherit from its parent using
53 * the CoreCLR inheritance rules.
55 * Base Type Allow Derived Type
56 * ------------ ------------------
57 * Transparent Transparent, SafeCritical, Critical
58 * SafeCritical SafeCritical, Critical
61 * Reference: http://msdn.microsoft.com/en-us/magazine/cc765416.aspx#id0190030
64 mono_security_core_clr_check_inheritance (MonoClass
*class)
66 MonoSecurityCoreCLRLevel class_level
, parent_level
;
67 MonoClass
*parent
= class->parent
;
72 class_level
= mono_security_core_clr_class_level (class);
73 parent_level
= mono_security_core_clr_class_level (parent
);
75 if (class_level
< parent_level
)
76 mono_class_set_failure (class, MONO_EXCEPTION_TYPE_LOAD
, NULL
);
80 * mono_security_core_clr_check_override:
82 * Determine if the specified override can "legally" override the
83 * specified base method using the CoreCLR inheritance rules.
85 * Base (virtual/interface) Allowed override
86 * ------------------------ -------------------------
87 * Transparent Transparent, SafeCritical
88 * SafeCritical Transparent, SafeCritical
91 * Reference: http://msdn.microsoft.com/en-us/magazine/cc765416.aspx#id0190030
94 mono_security_core_clr_check_override (MonoClass
*class, MonoMethod
*override
, MonoMethod
*base
)
96 MonoSecurityCoreCLRLevel base_level
= mono_security_core_clr_method_level (base
, FALSE
);
97 MonoSecurityCoreCLRLevel override_level
= mono_security_core_clr_method_level (override
, FALSE
);
98 /* if the base method is decorated with [SecurityCritical] then the overrided method MUST be too */
99 if (base_level
== MONO_SECURITY_CORE_CLR_CRITICAL
) {
100 if (override_level
!= MONO_SECURITY_CORE_CLR_CRITICAL
)
101 mono_class_set_failure (class, MONO_EXCEPTION_TYPE_LOAD
, NULL
);
103 /* base is [SecuritySafeCritical] or [SecurityTransparent], override MUST NOT be [SecurityCritical] */
104 if (override_level
== MONO_SECURITY_CORE_CLR_CRITICAL
)
105 mono_class_set_failure (class, MONO_EXCEPTION_TYPE_LOAD
, NULL
);
110 * get_caller_no_reflection_related:
112 * Find the first managed caller that is either:
113 * (a) located outside the platform code assemblies; or
114 * (b) not related to reflection and delegates
116 * Returns TRUE to stop the stackwalk, FALSE to continue to the next frame.
119 get_caller_no_reflection_related (MonoMethod
*m
, gint32 no
, gint32 ilo
, gboolean managed
, gpointer data
)
121 MonoMethod
**dest
= data
;
124 /* skip unmanaged frames */
128 if (m
->wrapper_type
!= MONO_WRAPPER_NONE
)
131 /* quick out (any namespace not starting with an 'S' */
132 ns
= m
->klass
->name_space
;
133 if (!ns
|| (*ns
!= 'S')) {
138 /* stop if the method is not part of platform code */
139 if (!mono_security_core_clr_is_platform_image (m
->klass
->image
)) {
144 /* any number of calls inside System.Reflection are allowed */
145 if (strcmp (ns
, "System.Reflection") == 0)
148 /* any number of calls inside System.Reflection are allowed */
149 if (strcmp (ns
, "System.Reflection.Emit") == 0)
152 /* calls from System.Delegate are also possible and allowed */
153 if (strcmp (ns
, "System") == 0) {
154 const char *kname
= m
->klass
->name
;
155 if ((*kname
== 'A') && (strcmp (kname
, "Activator") == 0))
158 /* unlike most Invoke* cases InvokeMember is not inside System.Reflection[.Emit] but is SecuritySafeCritical */
159 if (((*kname
== 'T') && (strcmp (kname
, "Type") == 0)) ||
160 ((*kname
== 'M') && (strcmp (kname
, "MonoType")) == 0)) {
162 /* if calling InvokeMember then we can't stop the stackwalk here and need to look at the caller */
163 if (strcmp (m
->name
, "InvokeMember") == 0)
167 /* the security check on the delegate is made at creation time, not at invoke time */
168 if (((*kname
== 'D') && (strcmp (kname
, "Delegate") == 0)) ||
169 ((*kname
== 'M') && (strcmp (kname
, "MulticastDelegate")) == 0)) {
171 /* if we're invoking then we can stop our stack walk */
172 if (strcmp (m
->name
, "DynamicInvoke") != 0)
187 * get_reflection_caller:
189 * Walk to the first managed method outside:
190 * - System.Reflection* namespaces
191 * - System.[MulticastDelegate]Delegate or Activator type
193 * and return a pointer to its MonoMethod.
195 * This is required since CoreCLR checks needs to be done on this "real" caller.
198 get_reflection_caller (void)
200 MonoMethod
*m
= NULL
;
201 mono_stack_walk_no_il (get_caller_no_reflection_related
, &m
);
203 g_warning ("could not find a caller outside reflection");
208 * check_field_access:
210 * Return TRUE if the caller method can access the specified field, FALSE otherwise.
213 check_field_access (MonoMethod
*caller
, MonoClassField
*field
)
215 /* if get_reflection_caller returns NULL then we assume the caller has NO privilege */
217 MonoClass
*klass
= (mono_field_get_flags (field
) & FIELD_ATTRIBUTE_STATIC
) ? NULL
: mono_field_get_parent (field
);
218 return mono_method_can_access_field_full (caller
, field
, klass
);
224 * check_method_access:
226 * Return TRUE if the caller method can access the specified callee method, FALSE otherwise.
229 check_method_access (MonoMethod
*caller
, MonoMethod
*callee
)
231 /* if get_reflection_caller returns NULL then we assume the caller has NO privilege */
233 MonoClass
*klass
= (callee
->flags
& METHOD_ATTRIBUTE_STATIC
) ? NULL
: callee
->klass
;
234 return mono_method_can_access_method_full (caller
, callee
, klass
);
240 * mono_security_core_clr_ensure_reflection_access_field:
242 * Ensure that the specified field can be used with reflection since
243 * Transparent code cannot access to Critical fields and can only use
244 * them if they are visible from it's point of view.
246 * A FieldAccessException is thrown if the field is cannot be accessed.
249 mono_security_core_clr_ensure_reflection_access_field (MonoClassField
*field
)
251 MonoMethod
*caller
= get_reflection_caller ();
252 /* CoreCLR restrictions applies to Transparent code/caller */
253 if (mono_security_core_clr_method_level (caller
, TRUE
) != MONO_SECURITY_CORE_CLR_TRANSPARENT
)
256 /* Transparent code cannot [get|set]value on Critical fields */
257 if (mono_security_core_clr_class_level (mono_field_get_parent (field
)) == MONO_SECURITY_CORE_CLR_CRITICAL
)
258 mono_raise_exception (mono_get_exception_field_access ());
260 /* also it cannot access a fields that is not visible from it's (caller) point of view */
261 if (!check_field_access (caller
, field
))
262 mono_raise_exception (mono_get_exception_field_access ());
266 * mono_security_core_clr_ensure_reflection_access_method:
268 * Ensure that the specified method can be used with reflection since
269 * Transparent code cannot call Critical methods and can only call them
270 * if they are visible from it's point of view.
272 * A MethodAccessException is thrown if the field is cannot be accessed.
275 mono_security_core_clr_ensure_reflection_access_method (MonoMethod
*method
)
277 MonoMethod
*caller
= get_reflection_caller ();
278 /* CoreCLR restrictions applies to Transparent code/caller */
279 if (mono_security_core_clr_method_level (caller
, TRUE
) != MONO_SECURITY_CORE_CLR_TRANSPARENT
)
282 /* Transparent code cannot invoke, even using reflection, Critical code */
283 if (mono_security_core_clr_method_level (method
, TRUE
) == MONO_SECURITY_CORE_CLR_CRITICAL
)
284 mono_raise_exception (mono_get_exception_method_access ());
286 /* also it cannot invoke a method that is not visible from it's (caller) point of view */
287 if (!check_method_access (caller
, method
))
288 mono_raise_exception (mono_get_exception_method_access ());
292 * can_avoid_corlib_reflection_delegate_optimization:
294 * Mono's mscorlib use delegates to optimize PropertyInfo and EventInfo
295 * reflection calls. This requires either a bunch of additional, and not
296 * really required, [SecuritySafeCritical] in the class libraries or
297 * (like this) a way to skip them. As a bonus we also avoid the stack
298 * walk to find the caller.
300 * Return TRUE if we can skip this "internal" delegate creation, FALSE
304 can_avoid_corlib_reflection_delegate_optimization (MonoMethod
*method
)
306 if (!mono_security_core_clr_is_platform_image (method
->klass
->image
))
309 if (strcmp (method
->klass
->name_space
, "System.Reflection") != 0)
312 if (strcmp (method
->klass
->name
, "MonoProperty") == 0) {
313 if ((strcmp (method
->name
, "GetterAdapterFrame") == 0) || strcmp (method
->name
, "StaticGetterAdapterFrame") == 0)
315 } else if (strcmp (method
->klass
->name
, "EventInfo") == 0) {
316 if ((strcmp (method
->name
, "AddEventFrame") == 0) || strcmp (method
->name
, "StaticAddEventAdapterFrame") == 0)
324 * mono_security_core_clr_ensure_delegate_creation:
326 * Return TRUE if a delegate can be created on the specified method.
327 * CoreCLR also affect the binding, so throwOnBindFailure must be
328 * FALSE to let this function return (FALSE) normally, otherwise (if
329 * throwOnBindFailure is TRUE) it will throw an ArgumentException.
331 * A MethodAccessException is thrown if the specified method is not
332 * visible from the caller point of view.
335 mono_security_core_clr_ensure_delegate_creation (MonoMethod
*method
, gboolean throwOnBindFailure
)
339 /* note: mscorlib creates delegates to avoid reflection (optimization), we ignore those cases */
340 if (can_avoid_corlib_reflection_delegate_optimization (method
))
343 caller
= get_reflection_caller ();
344 /* if the "real" caller is not Transparent then it do can anything */
345 if (mono_security_core_clr_method_level (caller
, TRUE
) != MONO_SECURITY_CORE_CLR_TRANSPARENT
)
348 /* otherwise it (as a Transparent caller) cannot create a delegate on a Critical method... */
349 if (mono_security_core_clr_method_level (method
, TRUE
) == MONO_SECURITY_CORE_CLR_CRITICAL
) {
350 /* but this throws only if 'throwOnBindFailure' is TRUE */
351 if (!throwOnBindFailure
)
354 mono_raise_exception (mono_get_exception_argument ("method", "Transparent code cannot call Critical code"));
357 /* also it cannot create the delegate on a method that is not visible from it's (caller) point of view */
358 if (!check_method_access (caller
, method
))
359 mono_raise_exception (mono_get_exception_method_access ());
365 * mono_security_core_clr_ensure_dynamic_method_resolved_object:
367 * Called from mono_reflection_create_dynamic_method (reflection.c) to add some extra checks required for CoreCLR.
368 * Dynamic methods needs to check to see if the objects being used (e.g. methods, fields) comes from platform code
369 * and do an accessibility check in this case. Otherwise (i.e. user/application code) can be used without this extra
370 * accessbility check.
373 mono_security_core_clr_ensure_dynamic_method_resolved_object (gpointer ref
, MonoClass
*handle_class
)
375 /* XXX find/create test cases for other handle_class XXX */
376 if (handle_class
== mono_defaults
.fieldhandle_class
) {
377 MonoClassField
*field
= (MonoClassField
*) ref
;
378 MonoClass
*klass
= mono_field_get_parent (field
);
379 /* fields coming from platform code have extra protection (accessibility check) */
380 if (mono_security_core_clr_is_platform_image (klass
->image
)) {
381 MonoMethod
*caller
= get_reflection_caller ();
382 /* XXX Critical code probably can do this / need some test cases (safer off otherwise) XXX */
383 if (!check_field_access (caller
, field
))
384 return mono_get_exception_field_access ();
386 } else if (handle_class
== mono_defaults
.methodhandle_class
) {
387 MonoMethod
*method
= (MonoMethod
*) ref
;
388 /* methods coming from platform code have extra protection (accessibility check) */
389 if (mono_security_core_clr_is_platform_image (method
->klass
->image
)) {
390 MonoMethod
*caller
= get_reflection_caller ();
391 /* XXX Critical code probably can do this / need some test cases (safer off otherwise) XXX */
392 if (!check_method_access (caller
, method
))
393 return mono_get_exception_method_access ();
400 * mono_security_core_clr_can_access_internals
402 * Check if we allow [InternalsVisibleTo] to work between two images.
405 mono_security_core_clr_can_access_internals (MonoImage
*accessing
, MonoImage
* accessed
)
407 /* are we trying to access internals of a platform assembly ? if not this is acceptable */
408 if (!mono_security_core_clr_is_platform_image (accessed
))
411 /* we can't let everyone with the right name and public key token access the internals of platform code.
412 * (Silverlight can rely on the strongname signature of the assemblies, but Mono does not verify them)
413 * However platform code is fully trusted so it can access the internals of other platform code assemblies */
414 if (mono_security_core_clr_is_platform_image (accessing
))
417 /* catch-22: System.Xml needs access to mscorlib's internals (e.g. ArrayList) but is not considered platform code.
418 * Promoting it to platform code would create another issue since (both Mono/Moonlight or MS version of)
419 * System.Xml.Linq.dll (an SDK, not platform, assembly) needs access to System.Xml.dll internals (either ).
420 * The solution is to trust, even transparent code, in the plugin directory to access platform code internals */
421 return (strcmp (accessed
->assembly
->basedir
, accessing
->assembly
->basedir
) == 0);
425 * mono_security_core_clr_level_from_cinfo:
427 * Return the MonoSecurityCoreCLRLevel that match the attribute located
428 * in the specified custom attributes. If no attribute is present it
429 * defaults to MONO_SECURITY_CORE_CLR_TRANSPARENT, which is the default
430 * level for all code under the CoreCLR.
432 static MonoSecurityCoreCLRLevel
433 mono_security_core_clr_level_from_cinfo (MonoCustomAttrInfo
*cinfo
, MonoImage
*image
)
435 int level
= MONO_SECURITY_CORE_CLR_TRANSPARENT
;
437 if (cinfo
&& mono_custom_attrs_has_attr (cinfo
, security_safe_critical_attribute ()))
438 level
= MONO_SECURITY_CORE_CLR_SAFE_CRITICAL
;
439 if (cinfo
&& mono_custom_attrs_has_attr (cinfo
, security_critical_attribute ()))
440 level
= MONO_SECURITY_CORE_CLR_CRITICAL
;
446 * mono_security_core_clr_class_level_no_platform_check:
448 * Return the MonoSecurityCoreCLRLevel for the specified class, without
449 * checking for platform code. This help us avoid multiple redundant
451 * - a check for the method and one for the class;
452 * - a check for the class and outer class(es) ...
454 static MonoSecurityCoreCLRLevel
455 mono_security_core_clr_class_level_no_platform_check (MonoClass
*class)
457 MonoSecurityCoreCLRLevel level
= MONO_SECURITY_CORE_CLR_TRANSPARENT
;
458 MonoCustomAttrInfo
*cinfo
= mono_custom_attrs_from_class (class);
460 level
= mono_security_core_clr_level_from_cinfo (cinfo
, class->image
);
461 mono_custom_attrs_free (cinfo
);
464 if (level
== MONO_SECURITY_CORE_CLR_TRANSPARENT
&& class->nested_in
)
465 level
= mono_security_core_clr_class_level_no_platform_check (class->nested_in
);
471 * mono_security_core_clr_class_level:
473 * Return the MonoSecurityCoreCLRLevel for the specified class.
475 MonoSecurityCoreCLRLevel
476 mono_security_core_clr_class_level (MonoClass
*class)
478 /* non-platform code is always Transparent - whatever the attributes says */
479 if (!mono_security_core_clr_test
&& !mono_security_core_clr_is_platform_image (class->image
))
480 return MONO_SECURITY_CORE_CLR_TRANSPARENT
;
482 return mono_security_core_clr_class_level_no_platform_check (class);
486 * mono_security_core_clr_method_level:
488 * Return the MonoSecurityCoreCLRLevel for the specified method.
489 * If with_class_level is TRUE then the type (class) will also be
490 * checked, otherwise this will only report the information about
493 MonoSecurityCoreCLRLevel
494 mono_security_core_clr_method_level (MonoMethod
*method
, gboolean with_class_level
)
496 MonoCustomAttrInfo
*cinfo
;
497 MonoSecurityCoreCLRLevel level
= MONO_SECURITY_CORE_CLR_TRANSPARENT
;
499 /* if get_reflection_caller returns NULL then we assume the caller has NO privilege */
503 /* non-platform code is always Transparent - whatever the attributes says */
504 if (!mono_security_core_clr_test
&& !mono_security_core_clr_is_platform_image (method
->klass
->image
))
507 cinfo
= mono_custom_attrs_from_method (method
);
509 level
= mono_security_core_clr_level_from_cinfo (cinfo
, method
->klass
->image
);
510 mono_custom_attrs_free (cinfo
);
513 if (with_class_level
&& level
== MONO_SECURITY_CORE_CLR_TRANSPARENT
)
514 level
= mono_security_core_clr_class_level (method
->klass
);
520 * mono_security_core_clr_is_platform_image:
522 * Return the (cached) boolean value indicating if this image represent platform code
525 mono_security_core_clr_is_platform_image (MonoImage
*image
)
527 return image
->core_clr_platform_code
;
531 * default_platform_check:
533 * Default platform check. Always TRUE for current corlib (minimum
534 * trust-able subset) otherwise return FALSE. Any real CoreCLR host
535 * should provide its own callback to define platform code (i.e.
536 * this default is meant for test only).
539 default_platform_check (const char *image_name
)
541 if (mono_defaults
.corlib
) {
542 return (strcmp (mono_defaults
.corlib
->name
, image_name
) == 0);
544 /* this can get called even before we load corlib (e.g. the EXE itself) */
545 const char *corlib
= "mscorlib.dll";
546 int ilen
= strlen (image_name
);
547 int clen
= strlen (corlib
);
548 return ((ilen
>= clen
) && (strcmp ("mscorlib.dll", image_name
+ ilen
- clen
) == 0));
552 static MonoCoreClrPlatformCB platform_callback
= default_platform_check
;
555 * mono_security_core_clr_determine_platform_image:
557 * Call the supplied callback (from mono_security_set_core_clr_platform_callback)
558 * to determine if this image represents platform code.
561 mono_security_core_clr_determine_platform_image (MonoImage
*image
)
563 return platform_callback (image
->name
);
567 * mono_security_enable_core_clr:
569 * Enable the verifier and the CoreCLR security model
572 mono_security_enable_core_clr ()
574 mono_verifier_set_mode (MONO_VERIFIER_MODE_VERIFIABLE
);
575 mono_security_set_mode (MONO_SECURITY_MODE_CORE_CLR
);
579 * mono_security_set_core_clr_platform_callback:
581 * Set the callback function that will be used to determine if an image
582 * is part, or not, of the platform code.
585 mono_security_set_core_clr_platform_callback (MonoCoreClrPlatformCB callback
)
587 platform_callback
= callback
;